US10069338B2 - Power receiver control circuit for wireless power receiver apparatus - Google Patents

Power receiver control circuit for wireless power receiver apparatus Download PDF

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US10069338B2
US10069338B2 US15/009,063 US201615009063A US10069338B2 US 10069338 B2 US10069338 B2 US 10069338B2 US 201615009063 A US201615009063 A US 201615009063A US 10069338 B2 US10069338 B2 US 10069338B2
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voltage range
target voltage
voltage
state
rectified
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US20160241083A1 (en
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Xun He
Daisuke Uchimoto
Takeshi Nozawa
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Rohm Co Ltd
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Rohm Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/80—Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Definitions

  • the present invention relates to a wireless power supply technique.
  • a wireless power supply method for supplying electric power to an electronic device
  • a wireless power supply method can be classified into two methods, i.e., the magnetic induction (MI) method and the magnetic resonance (MR) method.
  • MI magnetic induction
  • MR magnetic resonance
  • the MI method (1) the “Qi” standard developed by the WPC (Wireless Power Consortium) and (2) the standard developed by the PMA (Power Matters Alliance) (which will be referred as the “PMA standard” hereafter) have become mainstream.
  • FIG. 1 is a diagram showing a configuration of a wireless power supply system 100 R that conforms to the PMA standard.
  • the wireless power supply system 100 R includes a power transmitter (TX) apparatus 200 R and a power receiver (RX) apparatus 300 R.
  • the power receiver apparatus 300 R is mounted on an electronic device such as a cellular phone terminal, a smartphone, an audio player, a game machine, a tablet terminal, etc.
  • the power transmitter apparatus 200 R includes a transmission coil (primary coil) 202 , a driver 204 , a controller 206 , and a demodulator 208 .
  • the driver 204 includes an H-bridge circuit (full bridge circuit) or otherwise a half bridge circuit.
  • the driver 204 applies a driving signal S 1 , and specifically, which is configured as a pulse signal, to the transmission coil 202 .
  • a driving current flows through the transmission coil 202 .
  • the transmission coil 202 generates an electric power signal S 2 configured as an electromagnetic field signal.
  • the controller 206 integrally controls the overall operation of the power transmitter apparatus 200 R. Specifically, the controller 206 controls the switching frequency of the driver 204 , or otherwise the duty ratio of the switching operation thereof, so as to change the transmission power.
  • the power receiver apparatus 300 R includes a reception coil 302 , a rectifier circuit 304 , a smoothing capacitor 306 , a modulator 308 , a load 310 , a controller 312 , and a power supply circuit 314 .
  • the reception coil 302 receives the electric power signal S 2 from the transmission coil 202 . Furthermore, the reception coil 302 transmits a control signal S 3 to the transmission coil 202 .
  • the rectifier circuit 304 and the smoothing capacitor 306 rectify and smooth a current I RX induced at the reception coil 302 according to the electric power signal S 2 , thereby converting the current I RX into a DC voltage V RECT .
  • the power supply circuit 314 charges an unshown secondary battery using the electric power supplied from the power transmitter apparatus 200 , or otherwise steps up or steps down the DC voltage V RECT and supplies the DC voltage thus stepped up or down to the controller 312 or the load 310 configured as an external circuit.
  • a communication protocol is defined between the power transmitter apparatus 200 R and the power receiver apparatus 300 R.
  • Such a communication protocol allows the power receiver apparatus 300 R to transmit information to the power transmitter apparatus 200 R in the form of the control signal S 3 .
  • the control signal S 3 is transmitted from the power reception coil 302 (secondary coil) to the transmission coil 202 in the form of an AM (Amplitude Modulation) signal using backscatter modulation.
  • the control signal S 3 includes a power control signal (which will also be referred to as a “packet”) which controls an amount of electric power to be supplied to the power receiver apparatus 300 R, and data which indicates the identifying information for the power receiver apparatus 300 R.
  • the demodulator 208 demodulates the control signal S 3 included in the current or otherwise the voltage applied to the transmission coil 202 .
  • the controller 206 controls the driver 204 based on the power control signal included in the control signal S 3 thus demodulated.
  • the controller 312 of the power receiver apparatus 300 R monitors the electric power supplied to the load 310 , and generates, based on the monitoring result, a power control signal which indicates an amount of electric power to be supplied from the power transmitter apparatus 200 .
  • a target value is set for the rectified voltage V RECT .
  • an upper limit voltage V H and a lower limit voltage V L are set in the vicinity of the target voltage.
  • the controller 312 generates a power control signal D PC such that the rectified voltage V RECT is positioned within a target voltage range REF (between V L and V H ).
  • the PMA standard allows the power control signal D PC to switch between three states, i.e., (i) a state in which the transmission power is maintained (which will be referred to as the “first state ⁇ A ”), (ii) a state in which the transmission power is increased (which will be referred to as the “second state ⁇ B ”), and (iii) a state in which the transmission power is reduced (which will be referred to as the “second state ⁇ C ”).
  • the power transmitter apparatus 200 R changes a transmission frequency f TX according to the power control signal D PC received from the power receiver apparatus 300 , so as to control the electric power to be transmitted.
  • the transmission frequency f TX is maintained so as to maintain the transmission power.
  • the transmission frequency f TX is changed by a predetermined width ⁇ f UP (e.g., by multiple steps) so as to increase the transmission power.
  • the transmission frequency f TX is changed by a predetermined width ⁇ f DN (e.g., by a single step), so as to reduce the transmission power.
  • FIGS. 2A and 2B are waveform diagrams each showing the electric power control operation of the power supply system 100 R shown in FIG. 1 .
  • FIG. 2A shows the control operation in a non-oscillation state of the rectified voltage V RECT .
  • V RECT is lower than V L .
  • the controller 312 switches the power control signal D PC to the second state ⁇ B .
  • the controller 206 of the power transmitter apparatus 200 R changes the transmission frequency f TX by a predetermined width ⁇ f UP . As a result, the transmission power is increased, thereby increasing the rectified voltage V RECT .
  • the controller 312 switches the power control signal D PC to the third state ⁇ C .
  • the controller 206 of the power transmitter apparatus 200 R changes the transmission frequency f TX by a predetermined width ⁇ f DN .
  • the transmission power is reduced, thereby reducing the rectified voltage V RECT .
  • the power control signal D PC is maintained in the third state ⁇ C .
  • the transmission power is further reduced, thereby further reducing the rectified voltage V RECT .
  • V RECT is lower than V L . Accordingly, the power control signal D PC is switched to the second state ⁇ B . In response to this, the power transmitter apparatus 200 R changes the transmission frequency f TX by ⁇ f UP so as to raise the electric power to be transmitted. This increases the rectified voltage V RECT by ⁇ V UP1 .
  • the controller 312 switches the power control signal D PC to the third state ⁇ C .
  • the power transmitter apparatus 200 R changes the transmission frequency f TX by ⁇ f DN so as to reduce the electric power to be transmitted. This reduces the rectified voltage V RECT by ⁇ V DN2 .
  • the power control signal D PC is maintained in the third state ⁇ C . In this state, the transmission frequency f TX is further changed by ⁇ f DN , thereby further reducing the rectified voltage V RECT by ⁇ V DN3 .
  • the present invention has been made in order to solve such a problem. Accordingly, it is an exemplary purpose of an embodiment of the present invention to provide a wireless power receiver apparatus which is capable of suppressing oscillation.
  • An embodiment of the present invention relates to a control circuit for a wireless power receiver apparatus.
  • the wireless power receiver apparatus comprises: a reception coil; a rectifier circuit that rectifies a current that flows through the reception coil; and a smoothing capacitor connected to an output of the rectifier circuit.
  • the control circuit comprises: a target voltage range setting unit that sets an upper limit voltage and a lower limit voltage that define a target voltage range to be set for a rectified voltage that develops across the smoothing capacitor; an electric power control unit that generates a power control signal for controlling transmission power from the wireless power transmitter apparatus, based on a comparison result obtained by comparing the rectified voltage with each of the upper limit voltage and the lower limit voltage; and a modulator that generates a modulated signal by using the power control signal, and that transmits the modulated signal to the wireless power transmitter apparatus via the reception coil.
  • the target voltage range setting unit changes the target voltage range.
  • the rectified voltage in a state in which oscillation does not occur, the rectified voltage can be stabilized within a narrow target voltage range, thereby providing a high-efficiency operation.
  • the target voltage range is changed so as to suppress the occurrence of such oscillation.
  • detection of an oscillation state also includes detection of a sign which indicates that such oscillation will occur, in addition to detection of a state in which such oscillation has actually occurred.
  • the target voltage range setting unit may initialize the target voltage range.
  • the power control signal may be switchable between a first state indicative of maintaining the transmission power, a second state indicative of increasing the transmission power, and a third state indicative of decreasing the transmission power. Also, when the rectified voltage becomes lower than the lower limit voltage as a result of the power control signal being set to the third state, the target voltage range setting unit may judge that the rectified voltage is in the oscillation state.
  • the target voltage range setting unit may judge that the rectified voltage is in the oscillation state.
  • the rectified voltage changes so as to straddle the target voltage range. Accordingly, the rectified voltage remains in a state in which it deviates from the target voltage range.
  • such an arrangement is capable of appropriately detecting such an oscillation state.
  • the target voltage range setting unit may judge that the rectified voltage is in the oscillation state.
  • the power control signal does not remain at a constant value, i.e., it repeatedly changes.
  • such an arrangement is also capable of appropriately detecting such an oscillation state.
  • the power control signal may be switchable between a first state indicative of maintaining the transmission power, a second state indicative of increasing the transmission power, and a third state indicative of decreasing the transmission power. Also, when the power control signal remains in the first state for a predetermined time period, the target voltage range setting unit may judge that the rectified voltage is in the stable state.
  • the target voltage range setting unit may expand the target voltage range.
  • the target voltage range setting unit may expand the target voltage range by reducing the lower limit voltage.
  • such an arrangement is capable of suppressing the occurrence of such oscillation while suppressing degradation in the efficiency of the linear regulator. Furthermore, such an arrangement is capable of suppressing heat generation.
  • the target voltage range setting unit may expand the target voltage range by raising the upper limit voltage.
  • the target voltage range setting unit may shift the target voltage range.
  • such an arrangement is capable of suppressing the occurrence of such oscillation.
  • control circuit may conform to the PMA standard.
  • control circuit may monolithically be integrated on a single semiconductor substrate.
  • Examples of such a “monolithically integrated” arrangement include: an arrangement in which all the circuit components are formed on a semiconductor substrate; and an arrangement in which principal circuit components are monolithically integrated. Also, a part of the circuit components such as resistors and capacitors may be arranged in the form of components external to such a semiconductor substrate in order to adjust the circuit constants.
  • the wireless power receiver apparatus or the electronic device may comprise: a reception coil; a rectifier circuit that rectifies a current that flows through the reception coil; and any one of the aforementioned control circuits.
  • FIG. 1 is a diagram showing a configuration of a wireless power supply system that conforms to the PMA standard
  • FIGS. 2A and 2B are waveform diagrams each showing an electric power control operation of the power supply system shown in FIG. 1 ;
  • FIG. 3 is a block diagram showing an electronic device including a power receiver apparatus according to an embodiment
  • FIGS. 4A and 4B are operation waveform diagrams each showing the operation of the power receiver apparatus shown in FIG. 3 ;
  • FIGS. 5A and 5B are operation waveform diagrams each showing another example of the operation of the power receiver apparatus shown in FIG. 3 ;
  • FIG. 6 is a flowchart showing the control operation of a target voltage range setting unit.
  • FIG. 7 is a diagram showing an electronic device including the power receiver apparatus according to the embodiment.
  • the state represented by the phrase “the member A is connected to the member B” includes a state in which the member A is indirectly connected to the member B via another member that does not substantially affect the electric connection therebetween, or that does not damage the functions or effects of the connection therebetween, in addition to a state in which the member A is physically and directly connected to the member B.
  • the state represented by the phrase “the member C is provided between the member A and the member B” includes a state in which the member A is indirectly connected to the member C, or the member B is indirectly connected to the member C via another member that does not substantially affect the electric connection therebetween, or that does not damage the functions or effects of the connection therebetween, in addition to a state in which the member A is directly connected to the member C, or the member B is directly connected to the member C.
  • FIG. 3 is a block diagram showing an electronic device 500 including a power receiver apparatus 300 according to an embodiment.
  • the power receiver apparatus 300 receives an electric power signal S 2 from an unshown power transmitter apparatus, stores the electric power signal S 2 thus received in a smoothing capacitor 306 in the form of energy, and supplies the electric power to a load 502 .
  • the power receiver apparatus 300 includes a reception coil 302 , a rectifier circuit 304 , a smoothing capacitor 306 , and a control circuit 400 .
  • the power receiver apparatus 300 shown in FIG. 3 conforms to the PMA standard, and is applicable to the power supply system 100 R shown in FIG. 1 .
  • the reception coil 302 receives the electric power signal S 2 from the transmission coil 202 . Furthermore, the reception coil 302 transmits a control signal S 3 to the transmission coil 202 . A current I RX induced according to the electric power signal S 2 flows through the reception coil 302 .
  • the input side of the rectifier circuit 304 is connected to the reception coil 302 .
  • the rectifier circuit 304 full-wave rectifies or otherwise half-wave rectifies the current I RX .
  • the rectifier circuit 304 may be configured as a diode bridge circuit or an H-bridge circuit.
  • the smoothing capacitor 306 is connected to the output of the rectifier circuit 102 , so as to smooth the output voltage of the rectifier circuit 102 .
  • the DC voltage (which will be referred to as the “rectified voltage”) V RECT thus generated by the smoothing capacitor 306 is supplied to the load 502 configured as a subsequent stage.
  • the load 502 includes a power supply circuit 504 , a secondary battery 506 , and various kinds of circuits such as a processor 508 .
  • the power supply circuit 504 includes a linear regulator and/or a switching regulator (DC/DC converter).
  • the power supply circuit 504 regulates the rectified voltage V RECT to a suitable voltage level, and supplies the voltage thus regulated to the processor 508 .
  • the power supply circuit 504 may include a charger circuit that charges the secondary battery 506 using the electric power supplied from the power transmitter apparatus 200 .
  • the control circuit 400 includes a voltage measurement unit 402 , a target voltage range setting unit 404 , an electric power control unit 406 , and a modulator 408 .
  • the control circuit 400 is configured as a function IC (Integrated Circuit) monolithically integrated on a single semiconductor substrate. It should be noted that a part of the rectifier circuit 304 may be integrated on the control circuit 400 .
  • the voltage measurement unit 402 measures the rectified voltage V RECT that develops at the smoothing capacitor 306 or otherwise a voltage that corresponds to the rectified voltage V RECT .
  • the voltage measurement unit 402 may be configured as an A/D converter that generates a digital value D RECT which represents the measurement value of the rectified voltage V RECT .
  • the target voltage range setting unit 404 sets the upper limit voltage V H and the lower limit voltage V L that define the target voltage range REF for the rectified voltage V RECT that develops at the smoothing capacitor 306 . Specifically, the target voltage range setting unit 404 outputs digital values D H and D L that represent the setting values of the upper limit voltage V H and the lower limit voltage V L . In the present embodiment, the target voltage range REF is variable. Accordingly, at least one from among the upper limit voltage V H and the lower limit voltage V L is variable.
  • the electric power control unit 406 compares the rectified voltage V RECT with each of the upper limit voltage V H and the lower limit voltage V L , and generates a power control signal D PC based on the comparison result.
  • the PMA standard allows the power control signal D PC to switch between three states, i.e., (i) a state indicative of maintaining the transmission power (which will be referred to as the “first state ⁇ A ”), (ii) a state indicative of increasing the transmission power (which will be referred to as the “second state ⁇ B ”), and (iii) a state indicative of decreasing the transmission power (which will be referred to as the “third state ⁇ C ”).
  • the power transmitter apparatus 200 changes a transmission frequency f TX according to the power control signal D PC received from the power receiver apparatus 300 , so as to control the electric power to be transmitted. Specifically, when the power control signal D PC is set to the first state ⁇ A , the transmission frequency f TX is maintained, thereby maintaining the transmission power. When the power control signal D PC is set to the second state ⁇ B , the transmission frequency f TX is changed by a predetermined width (e.g., by multiple steps), so as to increase the transmission power. Conversely, when the power control signal D PC is set to the third state ⁇ C , the transmission frequency f TX is changed by a predetermined width ⁇ f DN (e.g., by a single step), so as to reduce the transmission power.
  • a predetermined width e.g., by multiple steps
  • the modulator 408 modulates the power control signal D PC so as to generate a modulated signal, superimposes the modulated signal on the current I RX through the reception coil 302 so as to generate a control signal S 3 , and transmits the control signal S 3 to the wireless power transmitter apparatus.
  • the target voltage range setting unit 404 raises the upper limit voltage V H and/or reduces the lower limit voltage V L , so as to change the target voltage range REF.
  • the target voltage range REF is expanded.
  • the target voltage range setting unit 404 initializes the target voltage range REF. Specifically, in this case, the upper limit voltage V H and the lower limit voltage V L are reset to their initial values V H0 and V L0 , respectively.
  • the unstable state ⁇ 3 includes the oscillation state ⁇ 1 .
  • FIGS. 4A and 4B are operation waveform diagrams each showing the operation of the power receiver apparatus 300 shown in FIG. 3 .
  • FIG. 4A shows the control operation in a non-oscillation state.
  • the operation waveform shown in FIG. 4A is the same as that shown in FIG. 2A .
  • the target voltage range REF is set to an initial state range REF 0 configured as the narrowest range.
  • the power control signal D PC is controlled according to the comparison result obtained by comparing the rectified voltage V RECT with each of the upper limit voltage V H0 and the lower limit voltage V L0 .
  • the transmission power is controlled, thereby stabilizing the rectified voltage V RECT within the target voltage range REF 0 .
  • FIG. 4B shows the control operation in the oscillation state.
  • the rectified voltage V RECT cannot be stabilized within the initial target voltage range REF 0 , and the rectified voltage V RECT enters the oscillation state ⁇ 1 .
  • the target voltage range setting unit 404 of the control circuit 400 expands the target voltage range REF.
  • the target voltage range setting unit 404 raises the upper limit voltage V H0 to the voltage level V H1 that is higher than the voltage level V H0 by one step.
  • the target voltage range REF is expanded to a target voltage range REF 1 .
  • the rectified voltage V RECT is controlled so as to be within the target voltage range REF 1 .
  • the rectified voltage V RECT is restored from the oscillation state ⁇ 1 to the stable state ⁇ 2 .
  • such an arrangement in a state in which such oscillation does not occur as shown in FIG. 4A , such an arrangement is capable of stabilizing the rectified voltage V RECT within the narrow target voltage range REF 0 .
  • the target voltage range REF is expanded, thereby suppressing the occurrence of oscillation.
  • the present inventors have investigated a technique (which will also be referred to as the “comparison technique”) in which the target voltage range REF 0 is configured to have a width ⁇ V that is greater than the maximum value of a possible voltage reduction ⁇ V DN .
  • a comparison technique ensures that the rectified voltage V RECT is positioned in the target voltage range between V L and V H in the step in which the transmission power is reduced in a stepwise manner according to the power control signal D PC .
  • the rectified voltage V RECT from falling into an oscillation state.
  • the rectified voltage V RECT becomes lower than the minimum level that is required to drive the load arranged as a downstream stage, leading to a problem in that the load cannot be driven.
  • the target voltage range REF is dynamically controlled instead of employing the target voltage range REF having a fixed width.
  • such an arrangement is capable of suppressing to a minimum the problem that can occur in the comparison technique.
  • FIGS. 5A and 5B are operation waveform diagrams each showing a different example of the operation of the power receiver apparatus 300 shown in FIG. 3 .
  • FIG. 4B shows an example in which, as a result of expanding the target voltage range REF by one step, such an arrangement is capable of resolving such an oscillation problem.
  • the target voltage range setting unit 404 repeatedly expands the target voltage range REF from REF 0 to REF 1 , REF 2 , and so forth, until such a problem of the occurrence of the oscillation state ⁇ 1 is resolved.
  • the target voltage range setting unit 404 raises the upper limit voltage V H in a stepwise manner from V H0 to V H1 , V H2 , . . . , V HN , so as to expand the target voltage range REF.
  • V HN represents the maximum value of the upper limit voltage V H .
  • the target voltage range setting unit 404 resets the target voltage range REF to the initial state REF 0 .
  • FIG. 5B shows an example in which the target voltage range REF is reset.
  • the stable state ⁇ 2 is maintained using the expanded target voltage range REF 3 .
  • the upper limit voltage V H is reset to the initial value V H0 , and accordingly, the target voltage range REF is reset to REF 0 .
  • the rectified voltage V RECT is higher than the upper limit voltage V H0 . Accordingly, the power control signal D PC is reduced, thereby reducing the rectified voltage V RECT .
  • the power control signal D PC is reduced at every time point t 2 , t 3 , and t 4 . As a result, the rectified voltage V RECT is eventually stabilized within the target voltage range REF 0 .
  • Such a control operation is represented by the solid line (i).
  • the line of alternately long and short dashes (ii) represents a waveform of the control operation in a case in which the target voltage range REF is not reset. It can be understood that, in a case in which the target voltage range REF 3 is maintained, the rectified voltage V RECT ′ is set to a relatively high voltage level. Such an arrangement leads to an increase in loss in the power supply circuit 504 configured as a downstream stage, resulting in degraded efficiency. In contrast, with the power receiver apparatus 300 according to the embodiment, such an arrangement is capable of resetting the target voltage range REF. Such an arrangement provides an operation with the rectified voltage V RECT having a low voltage level, thereby providing improved efficiency.
  • FIG. 6 is a flowchart showing the control operation of the target voltage range setting unit 404 .
  • the upper limit voltage V H is initialized to V H0 , thereby setting the target voltage range to REF 0 (S 100 ).
  • the lower limit voltage V L is initialized to V L0 .
  • the target voltage range setting unit 404 judges the state of the rectified voltage V RECT (S 102 ). In a non-oscillation state of the rectified voltage V RECT , the target voltage range REF is maintained (S 104 ). Upon detection of a transition from the stable state ⁇ 2 to the unstable state ⁇ 3 (YES in S 106 ), the target voltage range REF is initialized (S 100 ). During a period in which the stable state ⁇ 2 continues (NO in S 106 ), the target voltage range REF is maintained (S 104 ).
  • the target voltage range REF is expanded (S 104 ). Subsequently, judgment is made again regarding whether the state of the rectified voltage V RECT is the oscillation state or the non-oscillation state (S 102 ). With such an operation loop, the target voltage range REF is expanded until such an oscillation problem is resolved.
  • the target voltage range setting unit 404 judges that there is a sign of the oscillation state ⁇ 1 in the rectified voltage V RECT , and the target voltage range setting unit 404 changes the target voltage range REF.
  • the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the oscillation state ⁇ 1 , and may change the target voltage range REF.
  • the rectified voltage V RECT changes so as to straddle the target voltage range REF. Accordingly, deviation of the rectified voltage V RECT from the target voltage range REF continues.
  • a predetermined time period i.e., when the rectified voltage V RECT has not been positioned within the target voltage range REF in the predetermined time period, judgment is made that the rectified voltage V RECT is in the oscillation state ⁇ 1 .
  • the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the oscillation state ⁇ 1 . In other words, when the power control signal D PC remains in the first state ⁇ A for a predetermined judgment time period, the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the non-oscillation state.
  • FIG. 7 is a diagram showing an electronic device 500 including the power receiver apparatus 300 according to the embodiment.
  • the electronic device 500 shown in FIG. 7 is configured as a smartphone, a tablet PC, a portable game machine, or a portable audio player.
  • a housing 501 includes, as built-in components, a power supply circuit 504 , a secondary battery 506 , a processor 508 , a display apparatus 510 , and the aforementioned power receiver apparatus 300 .
  • the processor 508 may include a wireless (RF) unit, a baseband processor, an application processor, an audio processor, and the like.
  • RF wireless
  • the upper limit voltage V H is raised in a stepwise manner such that it is sequentially set to V H0 , V H1 , V H2 , . . . , V HN (it should be noted that V H0 ⁇ V H1 ⁇ V H2 . . . ⁇ V HN ), so as to expand the target voltage range REF.
  • the present invention is not restricted to such an arrangement.
  • the lower limit voltage V L may be reduced in a stepwise manner such that it is sequentially set to V L0 , V L1 , V L2 , . . . , V LN (it should be noted that V L0 >V L1 >V L2 . . . >V LN ), so as to expand the target voltage range REF.
  • both the upper limit voltage V H and the lower limit voltage V L may be changed.
  • the lower limit voltage V L may be reduced in a state in which the upper limit voltage V H is fixed to the initial value V H0 .
  • the upper limit voltage V H may be raised.
  • the upper limit voltage V H may be raised in a state in which the lower limit voltage V L is fixed to the initial value V L0 .
  • the lower limit voltage V L may be reduced.
  • the upper limit voltage V H and the lower limit voltage V L may be alternately changed.
  • the upper limit voltage V H and the lower limit voltage V L may be changed at the same time in increments of one step.
  • the power control signal D PC may be configured as multivalued data which indicates the transmission power or the transmission frequency.
  • the electric power control unit 406 changes the power control signal D PC in the first direction.
  • the rectified voltage V RECT becomes lower than the lower limit voltage V L
  • the electric power control unit 406 changes the power control signal D PC in the second direction.
  • the first direction represents the direction in which the power control signal D PC is increased.
  • the second direction represents the direction in which the power control signal D PC is reduced.
  • the electric power control unit 406 When the rectified voltage V RECT becomes higher than the upper limit voltage V H , the electric power control unit 406 reduces the power control signal D PC by one step. When the rectified voltage V RECT becomes lower than the lower limit voltage V L , the electric power control unit 406 increases the power control signal D PC by multiple steps.
  • the power transmitter apparatus 200 transmits electric power to the power receiver apparatus 300 according to the power control signal D PC .
  • the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the oscillation state.
  • the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the oscillation state.
  • the power control signal D PC does not remain at a constant value, i.e., it repeatedly changes. Such a method allows such an oscillation state to be appropriately detected.
  • the target voltage range setting unit 404 may judge that the rectified voltage V RECT is in the stable state.
  • the present invention is not restricted to such an arrangement. That is to say, a part of, or otherwise all of, either of the control operation of the electric power control unit 406 for the power control signal D PC or the control operation of the target voltage range setting unit 404 for the upper limit voltage V H and the lower limit voltage V L , or otherwise both of them, may be substituted by analog signal processing. For example, voltage comparison may be made using a voltage comparator.
  • the target voltage range setting unit 404 may shift the target voltage range REF in the upper direction or otherwise in the lower direction so as to suppress the occurrence of oscillation.
  • Such an arrangement is capable of providing improved stability of the rectified voltage V RECT as compared with an arrangement in which the target voltage range REF is expanded so as to suppress the occurrence of oscillation.
  • the target voltage range REF may be shifted in addition to expanded so as to suppress the occurrence of oscillation.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
US15/009,063 2015-02-05 2016-01-28 Power receiver control circuit for wireless power receiver apparatus Active 2036-10-22 US10069338B2 (en)

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